This proposal outlines two closely related projects, (1) production and evaluation of monoclonal antibodies that interfere with or mimic in vitro regulation of survival, growth and differentiation of cultured human neuroblastoma, (2) development of techniques to identify and eliminate neuroblastoma from bone marrow for antologous transplantation. The effects of humoral factors on the regulation of growth and differentiation of cultured human neuroblastoma (CHNB) cells will be examined by assay of clonal growth, morphological differentiation and phosphorylation of specific cell proteins. A panel of mouse monoclonal antibodies that bind to cell surface antigens of several CHNB cell lines will be generated. Effects on protein phosphorylation will be assayed to select mouse monoclonal antibodies that mimic or interfere with the biological actions of regulatory factors. In addition, mouse monoclonal antibodies that identify CHNB cell surface differentiation antigens will be generated. These monoclonal antibodies will be used to investigate growth and differentiation of neuroblastoma. Also, the therapeutic potential of these antibodies will be investigated. The antibodies will also be used to develop methods to identify and eliminate metastatic neuroblastoma cells in bone marrow in vitro, prior to treatment of neuroblastoma with autologous bone marrow transplantation. Monoclonal antibodies will be used to selectively kill neuroblastoma by antibody dependent, complement mediated cytotoxicity. Assays to detect and quantify neuroblastoma in bone marrow will use (1) monoclonal antibodies, binding of which will be detected by a sensitive two color immunofluorescence flow cytometric technique, and (2) selective growth of tumor cell colonies in soft agar.